Pad roller assembly



PAD ROLLER ASSEMBLYl Filed June 18, 1955 2 sheets-sheet ld i L 45 EM i`FIE'V E Y INVENTORS Ernest R055 BY AxEl EEllasnn i .WMe/M ATTORNEY.

March 9, 1937.

E. Ross ET AL PAD ROLLER ASSEMBLY Filed June 18, 1955 2 Sheets-Sheet 2INVENTORS. Ernest Ru 5 s ff ATTORNEY Patented Mar. 9, 1937 UNITED STATESPAD ROLLER ASSEMBLY Ernest Ross, Elmhurst, and Axel S. Eliason,Whitestone, N. Y., assignors to United Research Corporation, Long IslandCity, N. Y., a corpo'- ration of Delaware Application June 18, 1935,Serial No. 27,157

6 Claims.

This invention relates to motion picture apparatus and particularly tothe mechanism directly associated with the sprockets and rollers thatdrive and guide the film through the apparatus.

In the advancing of motion picture lm through cameras, projectors, soundunits, printers, and similar apparatus, sprockets are used for advancingthe lm past the various action points such as the picture taking andprojection apertures, sound translation points, and the printingapertures. The lm should travel or advance smoothly and uniformly overthese sprockets and it becomes necessary, therefore, that the film beheld on the sprockets at a uniform pressure and in a denite position.This is particularly true in printing apparatus such as the continuousreduction type of printer, wherein a 35 mm. negative, for instance, isbeing reduced to a 16 mm.

' positive by optical reduction. It is necessary in such printingoperations that the two films be held in perfect registry, which meansthat the drive must be uniform at all times and slippage of thelms ontheir sprockets be eliminated or reduced to a safe minimum.

The principal object of the present invention, therefore, is to hold alm on a drive sprocket so that the film travels smoothly and uniformlythereover. Features of the invention are the means provided formaintaining a uniform pressure on the film, the means for equalizing thepressure at all times, and the means for preventing film thicknessvariations or film splices from affecting the pressure on the film.

Other features and advantages of the invention will be apparent from thefollowing description read in conjunction with the accompanyingdrawings, in which Fig. l is an elevational view of a pair of padrollers embodying the invention applied to a reduction printer sprocket.

Fig. 2 is a detail section of the pad rollers of Fig. l taken along theline 2-2.

Fig. 3 is a detail section of the pad rollers of Fig. l taken along theline 3 3.

Fig. 4 is a front elevational View of a pad roller embodying theinvention applied to a single drive sprocket.

Fig. 5 is a sectional view of the pad roller of Fig. 4 taken along theline 5 5; and

Fig. 6 is a rear elevation of the pad roller of Fig. 4.

Referring now to Figs. l, 2, and 3, a reduction printer type of sprocketrotatably mounted on a supporting Wall 25 includes a large diametersection 5 and a smaller diameter section 6 which have been assembled torotate as a single unit after having been adjusted by pins and slotsshown at 1 to provide the proper registry between a negative iilmcarried by section 5 and a positive film carried by section 6 if thefilms are properly positioned on their respective sprocket teeth. A padroller assembly 9 functions to properly hold the negative film onsection 5 and a pad roller assembly I0 likewise functions for thepositive film on section 6.

The pad roller assembly 9 includes pad rollers I2 and I3 rotatablymounted at the ends of a curved arm I5 to which is pivoted a secondcurved arm IS which in turn is pivoted yat I1 and rotatably attached toan arm I8 on the opposite side of wall 25. The arm I6 has a bracket 20extending laterally therefrom in which is threaded a bolt 2l forlimiting the travel of the arm I6 and consequently the position of thepad rollers I2 and I3 with respect to sprocket section 5, the bolt 2|abutting an extension 23 mounted on the wall 25 of the printer (seeFigs. 2 and 3).

Rotatably mounted on one terminal of the arm I8 is a toggle rod 21slidable in a bearing 23 which is rotatably mounted in the wall 25. Aspring 33 under compression is positioned between the bearing 28 and ashoulder 3| on the rod 2l. intermediate the ends of arm I8, a pneumaticdash pot arm 33 is connected, this arm being connected to the piston ofa dash pot 34 which is permitted to rotate about a connection 3B (seeFig. 2).

A threaded bolt 31 is threadedly mounted in the arm I6 for positioningthe arm I5 with respect to arm IB. By the adjustment of this bolt thepressure of the pad rollers l2 and I3 may be equalized and-the padrollers be given a position to conform with the diameter of the section5 in the event of the use of different size sprockets. In the operationof this pad roller the spring maintains the pressure of the pad rollersat a uniform value upon the film travelling over the section 5. The padrollers do not come in contact with the surface of the sprocket but aremaintained at a distance slightly less than the minimum thickness of thelm by the adjustment of the screw 2I. The dash pot 34 eliminates anyjumps of the rollers in the case of inequalities in the film or lmsplices passing under the rollers. The dash pot also damps the naturalperiod of the spring 30 and also prevents the pad rollers from strikingthe sprocket with suicient force to dent the contact surfaces or injurethe sprocket teeth when the pad roller is closed.

For the smaller sprocket section 6, the pad roller ID includes a curvedarm 40 carrying pad rollers 4I and 42 rotatably mounted at the endsthereof. The arm 46 has pivoted thereto a curved arm 44 which is securedto a shaft 45 rotatably mounted within the Wall 25. An arm 41 on theopposite side of the wall 25 is also secured to shaft 45. The arm 40 istotally within the pitch circle of the teeth of sprocket section 5 whilethe arm 44 extends Within and Without it. The arm 44 has an extension 45therefrom which is threaded with a bolt 54 bearing on a stop 55 fastenedin the wall 25. This arrangement functions to adjust the position of arm44 and the bearing pressure of the pad rollers 4l and 42 upon thepositive ilm travelling over the sprocket section 6. A bolt 51 and atension spring 58 function to equalize the pressure of the pad rollers4| and 42 upon the sprocket section 6 when the proper adjustment ismade. A horn 59 is provided on the arm 44 to aid in releasing the padrollers from the sprocket.

The arm 41 is connected to a toggle rod 48 passing through a rotatablebearing 49, the rod 48 having mounted thereon a coil compression spring5D in the same manner as rod 21 for assembly 9. A pneumatic dash pot 52having a piston rod 53 is connected intermediate the ends of rod 41similar to the construction for assembly 9.

The pad roller IU just described operates in the same manner as the padroller 9 in that the compression spring 59 maintains a uniform pressureupon the positive lm on the sprocket section 6 While the dash pot 52damps oscillations and protects the sprocket from shock when the padrollers are closed.

In both of these pad roller assemblies the springs 311 and 59 alsofunction to hold the pad rollers in an inoperative position away fromthe sprockets for threading film in the machine. After the pivotconnections between the rod 21 and arm I8 and between the rod 48 and thearm 41 have passed dead center, the springs 30 and 50 reverse theiraction.

Referring noW to Figs. 4, 5, and 6, a pad roller assembly 62 is shownfor a single drive sprocket 6|. This pad roller includes a curved arm 63having mounted at one end thereof a pad roller 64 and intermediate theends, a pad roller 65. The other end of the arm 63 is secured upon ashaft 66 rotatably mounted within a bearing 8| in a Wall 14. A togglearm 68 on the opposite side of wall 14 is attached to shaft 56 to rotateWith arm 63. Pivoted on the end of arm 58 is a toggle rod B9 slidablymounted in an aperture in a ange of an L-shaped extension 1I (see Fig.5). Between the ange on the arm 1l and the toggle joint is a compressionspring 12 similar to the arrangement of rod 21 and spring 39 in Fig. 1.

This mechanism is all mounted on the Wall 14 which may be the same asWall 25 in Figs. 1, 2, and 3 if both sprockets are on the same machine.The arm 1l may be attached to the Wall 14 by means of screw 15, thebearing 8| extending through the Wall 14. Arm 63 has an extension 61which is positioned by a bolt 1E threaded through a stop 11 screwed inthe Wall 14. A knurled hand knob 18 is provided for releasing andpositioning the pad rollers 64 and 65 on the sprocket 6 I, the bolt 16adjusting the position of arm 61 and thus providing the desired pressurefor the pad rollers upon the film travelling over the sprocket 6I. Inthis assembly, the spring 12 also functions to hold the pad rollers inan inoperative position for threading the lm after the toggle joint haspassed dead center.

To prevent the arm 63 from swinging too far in the open position, a stopadapted to engage the extension 61 is mounted on the Wall 14. In

the modification shown in Figs. 1, 2, and 3, the dash pots limit theopen positions of the pad rollers.

What is claimed is:

1. A pad roller assembly for a lm sprocket for accommodating films ofdiiferent sizes comprising a iirst pad roller assembly including an armpivoted adjacent one end thereof, a second arm pivoted at the other endof said rst arm, pad rollers mounted on the ends of said second arm,spring tensioning means for maintaining said pad rollers against one ofsaid films at a substantially constant pressure and damping means connected to said spring tensioning means, and a second pad rollerassembly, including an arm pivoted adjacent one end thereof, a secondarm, pad rollers mounted at the ends of said second arm, springtensioning means for maintaining said pad rollers at a substantiallyconstant pressure against another of said lms, and individual dampeningmeans connected to said spring tensioning means for dampening theoscillations of said spring tensioning means.

2. A pad roller assembly in accordance with claim 1 in which saiddampening means comprises an individual dash pot connected to saidtensioning means.

3. A pad roller assembly for a sprocket for advancing lm of differentsizes having their longitudinal axes in a common plane, comprising asupporting wall, an arm pivoted on said wall and extending inside thepitch circle of the teeth of the larger sprocket, a second arm pivotedto said rst arm and having a pad roller at each end thereof, means foradjusting the position of said second arm with respect to said rst arm,a third arm pivoted to said Wall and extending outside the pitch circleof the teeth of the large sprocket, an arm pivoted on said lastmentioned arm and having pad rollers rotatably mounted at the endsthereof, and individual tensioning means for each arm attached to saidwall.

4. A pad roller assembly in accordance with claim 3 in which each ofsaid tensioning means has an individual dampening means.

5. A pad roller assembly in accordance with claim 3 in which said armsdirectly supporting said pad rollers have a curvature comparable to thecurvature of their respective sprockets.

6. A pad roller assembly for a lm sprocket adapted to accommodate lms ofdiiferent sizes comprising a rst pad roller assembly including an armpivoted adjacent one end thereof, a second arm pivoted at the end ofsaid rst arm, pad rollers mounted on the ends of said second arm formaintaining one of said lms at a definite position against one portionof said sprocket, spring tensioning means for maintaining said padrollers against said iilm at a substantially constant pressure anddamping means connected to said spring tensioning means, and a secondpad roller assembly including an arm pivoted adjacent one end thereof, asecond arm pivoted at the other end of said first arm, pad rollersmounted on the ends of said second arm for maintaining a second lm at adenite position against another portion of said sprocket, and springtensioning means for maintaining said pad rollers at a substantiallyconstant pressure against said other lm.

ERNEST ROSS. AXEL S. ELIASON.

